1. Field of the Invention
The present invention relates to a target detecting apparatus and target detection method which can detect targets such as pathogens, biological substances and toxic substances efficiently, reliably, simply and with high sensitivity, and to a target detection substrate which can suitably be used in this apparatus and method.
2. Description of the Related Art
In the related art, various kinds of methods have been considered for detecting targets such as pathogens, biological substances and toxic substances, for example, enzyme immunoassay methods such as ELISA. However, in these methods, there was the problem of having to use expensive fluorescent labels or dangerous radiation markers.
Recently, an apparatus and method have been proposed which detect targets by detecting an interference color change of interference light by unit of a detection layer without using a fluorescence label or a radiation marker. For example, an apparatus has been proposed which measures a thickness change of a nonspecific protein layer as an interference color change using an ellipsometer or the like (e.g., JP-A No. 2002-122603 and JP-A No. 2002-116208). In another method, a thickness change is detected as an interference color change in a light reflecting surface by a nucleic acid chain (e.g., JP-B No. 07-32720, JP-A No. 10-288616 and JP-A No. 2001-235473). An apparatus has been proposed wherein light emitted from a light source is irradiated onto a sample surface via a polarizer, the reflected light is reflected by a polarization modulator, and then detected via a polarizer (e.g., JP-A No. 61-34442, JP-A No. 04-78122, JP-B No. 62-57936 and U.S. Pat. No. 4,332,476). Moreover, an apparatus has been proposed which measures a thickness change of a nonspecific protein layer as an interference color change using an ellipsometer or the like, and detects this interference light via a polarizer (e.g., JP-A No. 2002-122603).
However, simple and quick measurement cannot be performed in these cases, and there are problems in that the apparatus easily picks up measurement noise, the measurement error is large, measurement sensitivity is poor and a quantitative measurement cannot be made. Therefore, in the present situation, there was no target detecting apparatus and target detecting method which could detect targets such as pathogens, biological substances and toxic substances without using a costly measuring apparatus, which could detect them with a low measurement error, high efficiency, simplicity, rapidity and sensitivity, and make a quantitative measurement, nor a target detection substrate which could be used in such an apparatus and method, and so the development thereof was eagerly awaited.
Objects and Advantages
It is therefore an object of the present invention to provide a target detecting apparatus and target detecting method which can detect targets such as pathogens, biological substances and toxic substances without using a costly measuring apparatus, which can detect these targets with a low measurement error, high efficiency, simplicity, speed and sensitivity, and make a quantitative detection thereof, and to provide a target detection substrate which can be used in such an apparatus and method.